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The Marangoni effect induced by organic vapor has drawn considerable attention in integrated circuit manufacturing for eliminating watermark defects encountered in the wafer drying process. Accordingly, a vertical rotational Marangoni (VRM) dryer based on the combination of the Marangoni effect and centrifugal force is proposed and developed. In particular, the hydrodynamic behavior of the VRM dryer is investigated to reveal the mechanism of ultraclean drying. A three-dimensional model of the VRM dryer is proposed, and the flow field of the water film and distribution of organic species are adequately analyzed. The results show that the rotational velocity and wettability significantly affect the coverage uniformity of the water film, and the exposure region at the three-contact line leads to the watermark. Furthermore, the coupling behavior of the Marangoni effect and centrifugal force is revealed. A higher rotational velocity leads to worse integrity of the water film covering, and thus, fainter Marangoni effect. Polishing and cleaning experiments are conducted to verify the effectiveness of theoretical analysis. The results indicate that the optimized rotational velocity for the hydrophilic surface is higher than that of the hydrophobic surface. The mechanism analysis of wafer drying based on the VRM drying technology provides effective guidance for ultraclean surface manufacturing during the cleaning process.

Cleaning processes draw considerable attention in integrated circuit manufacturing because of the rapid development of technology nodes. Bare silicon wafer cleaning after chemical mechanical polishing (CMP) is one of the most difficult processes used to meet the extremely strict industrial requirements. Herein, the silicon wafer cleaning mechanism is studied in detail. The effects of megasonic and brush cleaning on nanoparticle removal are both analysed through experiments and simulations. The experimental results show that chemical concentration, megasonic vibration power, and brush clamp gap all significantly affect the cleaning performance, and that excessive megasonic power reduces the cleaning performance because more defects are introduced. A model of megasonic nozzle trajectory is also proposed, and optimized parameters, especially the relative velocity between the wafer rotation and nozzle movement, are critical to removing nanoparticles effectively. Furthermore, analysis of combining megasonic and brush cleaning shows that including megasonic cleaning improves the wafer cleaning performance by several orders of magnitude. Based on the optimized cleaning conditions, an ultraclean wafer surface is achieved after CMP.

Marangoni drying is a highly concerned technology in the integrated circuit (IC) manufacturing, which removes the deionization (DI) water on the wafer surface in the wet cleaning process after chemical mechanical polishing (CMP). When the wafer is withdrawn from a DI water bath, Marangoni effect is induced by the organic vapor blown at the meniscus. It contributes to the backflow and stripping of the entrained water on the wafer and then achieves an ultraclean surface. Herein, the Marangoni drying performance is experimentally investigate using a self-developed drying device. Firstly, the visible water film on the wafer surface before and after Marangoni drying is observed. It indicates that Marangoni effect dramatically increases the critical withdrawal velocity where the visible water is formed. Further, the fluorescent particles are added in DI water, and the drying performance is characterized by counting the deposited particles using a fluorescent microscope. Such a method indirectly reflects the drying performance. The experimental results show that withdrawal velocity, organic vapor flux and blown angle exert significant impacts on the drying performance.

Wafer drying induced by Marangoni effect is crucial to achieving an ultraclean surface in integrated circuit manufacturing. According to the previous opinions, the entrained water film on wafer surface was stripped by Marangoni effect, and thus the watermark defect induced by evaporation was inhibited. However, the influence of particle removal induced by Marangoni effect on the ultraclean surface preparation is lack of adequate understanding. The present work implements an experimental and numerical investigation of wafer cleaning behavior engendered by Marangoni effect during the wafer withdrawn process. The impacts of critical process parameters and substrate properties on the particle removal efficiency are systematically studied. The results show that Marangoni effect has better cleaning performance on the glass substrate compared with that of silicon and copper. The numerical simulation indicates that the Marangoni effect is more dramatic on glass substrate owing to the better wettability. Furthermore, the stress analysis reveals the adsorption force of fluorescent particle on the copper surface is stronger than that of silicon and glass. Therefore, particle cleaning on the copper surface is much more difficult. The investigation of cleaning performance driven by the Marangoni effect will contribute to a comprehensive understanding of the mechanism of ultraclean surface preparation.